The clutch is a type of device for transferring power from the mechanic engine of an automobile, a motorcycle or other power sources to the wheel shaft of the automobile in an attach-detach fashion, which can be typically categorized into so-called dry clutches and wet clutches, and the structural differences between them are that the wet clutch is installed in a sealed oil chamber, while the dry clutch can be placed in a ventilated, dry environment. According to currently available crafts for automobile fabrications, such two sorts of clutches have their respective advantages, in which the wet clutch may have an extended life span through engine oil lubrications thus lowering the heat and abrasions caused by frictions; however, the wet clutch may be accompanied by significantly higher costs and greater structural sizes.
Contrarily, the dry clutch needs not to be immersed in the engine oil, thus allowing more direct and acute power transmissions, also enabling more powerful torque and acceleration than the wet clutch; besides, since the drive disc and the passive disc are not placed in the engine oil, these two components may be conveniently taken apart in absence of viscosity of the engine oil, thus eliminating the requirement on the separation elastic plate additionally installed for ensuring the separation between the drive disc and the passive disc and preventing the risk of clutch deadlock problems, also further simplifying the integral structure of the clutch; whereas, it should be known the lack of engine oil lubrication may cause relatively greater abrasions in the drive disc and the passive disc, so the life span thereof could be shortened to a notable extent; in particular, the increased torque may lead to the slip issue in case of uneven force distributions. Therefore, through the above-said comparisons, it can be appreciated that, although the objectives of the dry and the wet clutches may be essentially the same, their structures may be two parallel solutions, not mutually compliant, and no room for parts of such structures to exhibit the possible existence of collaborative mixture.
One type of common dry clutch applicable for motorcycles can be referred to FIG. 1. When a user presses down the accelerator to initialize, the transmission component 15 drives the dry clutch 1 to spin synchronously, and, upon reaching at a predetermined rotation speed (typically about 3000 rotations per minute (RPM)), the three clutch counter-weights 11 in the dry clutch 1 may overcome the flexibility restriction from the springs 12 by means of inertial reaction force (commonly referred as the centrifugal force) and be flung outwardly such that the linings 13 on these clutch counter-weights 11 may gradually engage and abut closely to the clutch shell 14 to rotate at the same pace thereby driving the vehicle to move forward. However, due to long-termed and repeated abrasive driving, the extent of elastic fatigue occurring on each of the springs 12 may not be identical, thus leading to variations in terms of fling time, distance etc. on each of the clutch counter-weights 11. Accordingly, because of such accumulations, the differences in abrasions among such three linings 13 set forth in the present instance may become more significant. Suppose one of them gradually fails, i.e., simply a smaller area thereof may engage with the clutch shell 14 rather than a complete attachment, the drive efficiency applied on the clutch shell 14 through the drive synchronous rotations may be undesirably reduced, or even causing instability problems in the intended conjunctive movement effect.
Accordingly, those skilled ones in the art proposed certain improvements with regards to the aforementioned issues found on the dry clutches, in which the coordinate structure configured between the clutch counter-weights and the springs is removed, as illustrated in FIG. 2, and alternatively a push-up disc 22 to be squeezed and pressed by the centrifugal rollers 21 installed on the disc (not denoted) is applied. During the squeezing and pressing process, the springs 23 are coerced to be retracted tightly such that the block-wise linings 24 set up on the push-up disc 22 can rise up toward the up direction in the plane of the Figure so as to frictionally engage with the clutch shell 25 thereby driving the clutch shell 25 to rotate for power transmissions. However, the torque transmission achieved by such a design is essentially undertaken entirely by one single columnar guide pin 231, so that in case the engine has been initiated to rotate, not reaching at a predetermined rotation speed yet, the clutch shell 25 is not driven, but the lower end of the columnar guide pin 231 for stabilizing the spring 23 may be subject to the torque first; on the contrary, the upper end thereof may be synchronized to the clutch shell 25 and unable to move, thus two opposite drive directions on such two ends may lead to synchronous rotation failures. Upon slowing down, the rotation speed of the wheels can be reduced by the braking effect, so the columnar guide pin 231 has to be subject to another torque of non-synchronous speeds once again.
After long-termed use, since the torque may be variant and intermittent, suppose certain portions around the upper and lower ends on the columnar guide pin 231 do have material non-uniformity problems, fissures may appear in such portions due to stress concentrations, or even probably leading to serious breakage or fracture on the integral structure; in case the fractures do occur, the synchronous operation of the dry clutch may abruptly stop, resulting in void engine operation and power failures for the automobile, thus causing tremendous vehicular cruise risk. Moreover, as shown in the Figure, seeing that the block-wise linings 24 move upwardly and come into direct contact with the clutch shell 25, the heat energy generated by mutual frictions may be accumulated on the clutch shell 25, and the damages to the structure of the clutch shell 25 resulting from such repeated expansion-retraction processes caused by heat energy fluctuations may be quite difficult to measure, thus greatly shortening the life span of the dry clutch.
Based on the aforementioned drawbacks explained in the prior art structural improvements, the present invention provides a saddle ride type vehicular dry clutch having passive clutch disc of co-axial fixed plane contact, in which the drive bearing assembly follows the power transmissions from a belt to continuously rotate, and when the rotation speed achieves a certain specific value, the radially allocated centrifugal rollers may be flung outwardly and abut tightly and engage with the passive clutch disc which further contacts the friction drive disc. Since such two elements are jointed by a surface engagement of large areas, it is possible to effectively resolve the uneven lining contact surface issue and eliminate the coordinate structure using springs for controlling the fling distance of clutch counter-weights, thus avoiding the elasticity aging problem which may adversely affect the feature of uniform power transmissions. Once the drive disc starts to rotate synchronously, the clutch shell can acquire the needed power for rotations through transmissions of the fixation parts snap fixed with the drive snap ports, and further drive the for output axle with the acquired power by means of the central occlusive hole thus enabling the operations of the mechanic power equipment. In addition, since the friction engagement objects are altered from the previous linings (equivalent to the above-said drive disc) and the clutch shell to the passive clutch disc and the drive disc, the direct frictional contact to the clutch shell may be reduced thus lowering the possibility of structure damages due to physical effects such as expansion-retraction phenomenon or the like. Besides, the installation positions for springs have been ameliorated so as to prevent the fracture problem in the aforementioned columnar guide pin because of stresses, thereby extending the life span of the entire dry clutch and maintaining the power transmission efficiency. Thus the major features of the present invention are illustrated.